DEFORMATION COMPENSATION OF A STABILIZED RESONATOR UNDER HIGH PRESSURE CHANGE BASED ON A MODIFIED POUND-DREVER-HALL METHOD

Duong Quang Anh, Tomokage Syunsaku, Masato Aketagawa

Abstract

Recently, the resolution of length measurements based on optical interferometry reached sub-nanometer order. However, the accuracy of the optical interferometry is limited by the knowledge of absolute air refractive index. In this work, we have proposed a method to measure the absolute air refractive index by measuring the free-spectral-range and the resonance frequency of a Fabry-Perot cavity, whose inside is filled by vacuum and by air. During the air refractive index measurement, the geometrical length of the Fabry-Perot cavity must be constant in vacuum and in air. In this paper, a compensation of the Fabry-Perot cavity length deformation owing to a large pressure difference between air and vacuum is proposed.

Keywords

air refractive index, Fabry-Perot cavity, Free spectral range, Resonance frequency, Pound-Drever-Hall method

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DOI

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IMEKO TC

TC14 - Measurement of Geometrical Quantities

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